package com.fengye.algorithms.huawei;

import java.util.Scanner;

/**
 * @Author fengye
 * @Date 2023/4/7 11:03
 **/
public class Yanghui2Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int a = in.nextInt();
            if(a<=2) {
                System.out.println(-1);
                return;
            }
            int n = (a-2)%4;
            if(n==1) {
                System.out.println(2);
            } else if(n==2) {
                System.out.println(3);
            } else if(n==3) {
                System.out.println(2);
            } else {
                System.out.println(4);
            }
        }
    }
}
